So the disclosures in recent days by the official Xinhua News Agency and People’s Daily that gross domestic product figures in China’s northeastern rust-bowl region were doctored was less surprising. What was noteworthy was that official media made the episode so public, suggesting official tolerance for official fudging is on the wane.

The articles cite an anticorruption investigation after which they said local officials in the northeast provinces of Heilongjiang, Jilin and Liaoning admitted they had been falsifying economic data for years. The practice has encouraged corruption, undermined faith in the Communist Party-led government and led to distorted policy decisions, the articles said, without providing specific examples.

The scale was such that the official data generated by some counties alone suggested that their economies rivaled Hong Kong’s in size, Xinhua said, quoting Jilin lawmaker Zhao Zhenqi. Mr. Zhao couldn’t be reached.

Economists and analysts said they read a few things into the timing of the disclosures. While massaging figures is common among Chinese provinces, the practice appears more pronounced recently in the northeast – China’s slowest-growing region this year -- given weak exports, stumbling resource and manufacturing industries and struggling real estate investment, some said.

"'Water injection in GDP figures' exists all over China,” said Wei Yihua, economics professor at Jilin University, referring to the practice of infusing pork with liquid to boost its price. “But it’s more obvious in backward areas because they have no way to develop the economy, so their only option is to play with the statistics.”

Off-target: Heilongjiang is one of three northeastern Chinese provinces that have doctored their GDP data, according to Chinese state media reports.

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In the first three quarters of 2015, China’s slowest-growing province of Liaoning reported a 21.2% contraction in investment, a 24.8% decline in nominal profits and a 7.6% drop in industrial output. “Yet they still posted 2.7% real growth,” said IHS Global Insight economist Brian Jackson. “That’s quite a bit to swallow.”

The apparent gap suggests either that Liaoning saw a huge surge in consumption, which isn’t supported by household-income data, or a boom in services. “That’s not impossible, but somewhat dubious given that manufacturing has collapsed,” Mr. Jackson said. “Most indications are that the northeast is already in recession.”

The Liaoning provincial government didn't respond to questions.

For northeastern officials under investigation, pointing out past mistakes and vowing to reform their ways may have helped blunt the pressure they were under for not helping China reach its about 7% national growth target this year, analysts said. In an April visit to the northeast, the premier told local officials they needed to spur growth in order to shore up employment and people’s incomes, according to Xinhua.

The timing also suggests that President Xi Jinping is now confident enough to take on some well-entrenched bureaucratic practices and is sending a signal to more powerful provinces that they need to clean house, analysts said.

With local promotions tied to growth figures, there has been a big incentive to fudge, said Oliver Rui, finance professor with the China Europe International Business School. And China’s statistical agency isn’t independent and relies on inflated provincial figures to meet its national growth target, he added.

“In some ways local officials are encouraged to do this because the central government has an incentive to look good to the country and the world,” Mr. Rui said.

China’s National Bureau of Statistics didn’t respond to questions.

All countries' growth statistics, including Washington’s, have problems, but experts say it’s important to maintain acceptable margins of error. China has pledged to follow more stringent United Nations and International Monetary Fund standards to improve transparency and credibility.

China also has talked about creating a system that puts less emphasis on one growth number in handing out local promotions. While measuring performance based on quality-of-life issues can be difficult in practice, one place to look is corporations, say management consultants, which have decades of experience motivating employees based on a variety of soft and concrete benchmarks.